Progression-free survival (PFS) and overall survival (OS) in patients (pts) with de-novo, high-volume metastatic castration-sensitive prostate cancer (dn-hv-mCSPC) undergoing intensified androgen deprivation therapy (ADT).

Abstract

133 Background: In the PEACE-1 trial (Fizazi, ESMO 2021), in pts with dn-hv-mCSPC, the addition of abiraterone to ADT + docetaxel (triplet therapy arm) resulted in a median OS of 61 months (OS on ADT + docetaxel arm was 42 months). However, independent contribution of docetaxel to efficacy of ADT + abiraterone in the triplet therapy arm of PEACE-1 trial is not clear. Furthermore, the efficacy of an novel hormonal therapy (NHT) specifically in dn-hv-mCSPC population has not been reported (LATITUDE trial’s eligibility did not include volume status). Herein, our objective was to assess PFS and OS in a cohort of dn-hv-mCSPC pts undergoing intensified ADT with either NHT (i.e. novel androgen receptor or androgen synthesis inhibitors) or docetaxel. Methods: In this IRB-approved study, patient-level data were collected retrospectively. Eligibility: presence of dn-hv-mCSPC (hv per CHAARTED criteria) undergoing intensified ADT with either NHT or docetaxel started within 3 months of diagnosis. Study endpoints: PFS was calculated per PCWG-2 - defined PSA progression or radiographic progression or clinical progression whichever occurred first; OS was defined as start of therapy to date of death or censored at last follow-up. A multivariate analysis using the Cox proportional hazards (Cox-ph) model was used; the relationship between treatment intensification with both PFS and OS was assessed and adjusted for age at diagnosis, Gleason score, presence of visceral metastases, and PSA at baseline. Results: 85 pts with dn-hv-mCSPC were included: 45 received ADT + NHT; 40 received ADT + docetaxel. In the NHT vs docetaxel arms: median PFS were 23 vs 14 months; and median OS were 63 vs 36 months respectively. See the table for Cox-ph and adjusted co-variate results. Conclusions: We for the first-time report the real-world survival outcomes with ADT + NHT specifically in pts with dn-hv-mCSPC. In addition, in these hypothesis-generating data, the OS of pts with dn-hv-mCSPC undergoing ADT + NHT or ADT + docetaxel were similar to those in the triplet therapy arm or ADT + docetaxel arm of PEACE-1 trial respectively. A randomized trial in pts with dn-hv-mCSPC comparing ADT + NHT vs triplet therapy may better characterize the benefit of the docetaxel component in the triplet therapy.[Table: see text]